An inkjet printing apparatus includes a transport mechanism transporting web paper (a print medium), and printing heads each discharging ink to the web paper to be transported. The inkjet printing apparatus performs line flushing periodically at a position of an ink receiver to avoid clogging. In the line flushing, all nozzles of the printing heads discharge ink. See, for example, Japanese Unexamined Patent Publications No. 2002-225305A and 2005-262551A. The line flushing is performed to a non-printable region between printable regions of image data represented by characters, figures, and pictures. The non-printable region is not used as a printable region of the image data.